dealbook.nytimes.com – Photo Email Share Tweet Save More DealBook Column Related Links Timeline: A Rocky Path to Allergan’s Deal Deal Thwarted by a Company Newly Irish Mega-Mergers Popular Again on Wall Street Heads he wins. Tails he wins. That was the situation William A. Ackman, the hedge fund manager and founder of Pershing Square Capital Management, found himself in — or perhaps more accurately, orchestrated — on Monday.